The field of microfluidics has advanced rapidly. These advancements relate to the development of large-scale integration of microfluidic circuits, and numerous applications of microfluidics to life science research. Currently, optical microscopy is employed in microfluidic research as a technique to study fundamental microscale flow physics as well as biological targets. It is also used to study processes that are performed within these integrated microfluidic systems. In general, these devices rely on a macro-scale infrastructure (e.g. bulk microscopes, chip readers) to analyze biological targets.
Near field scanning optical microscopes (NSOMs) are extensively used to study biological targets. NSOMs can optically resolve structures with spatial resolutions of ˜50 nm. An NSOM uses a strongly enhanced and tightly confined optical field at the end of an NSOM probe tip to optically probe a specific location on a target sample. NSOMs are especially useful for profiling bacteria, because bacteria cannot be easily imaged with conventional optical microscopy. In comparison to other high resolution imaging devices, such as scanning electron microscopes, NSOMs are able to selectively map the distribution of proteins or biochemicals in samples via fluorescence. In addition, NSOM imaging methods are non-destructive and can be used to image bioentities that are immersed in buffer media. Given all these advantages, one would expect that NSOMs would be widely used in clinical applications to distinguish bacteria types. However, the lack of publications on this suggests that significant technical barriers exist to using NSOMs. One such barrier is the difficulty of performing high throughput imaging with an NSOM. High throughput imaging requires raster scanning the probe tip over a target bioentity.
Embodiments of the invention are directed to devices which are improvements over NSOMs and conventional microfluidic systems that use bulky optics.